On closing, I have to again download the files so as to enter offline mode

[Vardhman-jain]

When I close Pokerogue, I have to again redownload the files for the offline version and my progress is not saved

[Admiral-Billy]

That sounds like there's an extra copy of the game sitting open in the background or something, which will cause weird stuff to happen; try opening task manager to make sure there's no extra copies open (since it gets stuck sometimes) or restarting the computer to forcibly close any extra copies.